tingling sensation in foot fingers

My dada is suffering from a strange thing, he always complains of tingling sensation in the foot fingers. always ha says that he feels as if " pair so gaye hai aur jhanjnahat rehtli hai" he 75 and we showed him to the doctor also. but after a long medication things remains the same.

anybody any idea. doctor says this is due to less blood flow in old age but is this very common. Please advice if anybody came across any such thing. He does regular exercise.